1. Field of the Invention
The present invention relates to the field of sensor technology and, in particular, to implantable, in-vivo sensing systems used for sensing a variety of parameters, including physiological parameters.
2. Description of Related Art
The combination of biosensors and microelectronics has resulted in the availability of portable diagnostic medical equipment that has improved the quality of life for countless people. Many people suffering from disease or disability who, in the past, were forced to make routine visits to a hospital or doctor's office for diagnostic testing currently perform diagnostic testing on themselves in the comfort of their own homes using equipment with accuracy to rival laboratory equipment.
Nonetheless, challenges in the biosensing field have remained. For example, although many diabetics currently utilize diagnostic medical equipment in the comfort of their own homes, the vast majority of such devices still require diabetics to draw their own blood and inject their own insulin. Drawing blood typically requires pricking a finger. For someone who is diagnosed with diabetes at an early age, the number of self-induced finger pricks over the course of a lifetime could easily reach into the tens of thousands. In addition, the number of insulin injections may also reach into tens of thousands. Under any circumstances, drawing blood and injecting insulin thousands of times is overly invasive and inconvenient at best and most likely painful and emotionally debilitating.
Some medical conditions have been amenable to automated, implantable sensing. For example, thousands of people with heart conditions have had pacemakers or defibrillators implanted into their bodies that utilize sensors for monitoring the oxygen content of their blood. Ideally, these sensors should be able to determine whether, for example, a person's heart is running very efficiently at a high heart rate or whether a person's heart has entered defibrillation. In order to effectively make this determination, an accurate sensor must be employed. Unfortunately, oxygen sensors implanted into the body have, thus far, typically required frequent and periodic checking and recalibration. In fact, one of the “holy grails” of the pacemaker industry has been an accurate, no drift, no calibration oxygen sensor. Up until now, such a sensor has been unavailable.
An ideal solution to the diagnostic requirements of those with disease or disability, absent an outright cure, is a sensing apparatus that may be implanted into the body and that may remain in the body for extended periods of time without the need to reset or recalibrate the sensor. Regardless of the particular application for such a sensor system, in order to effect such a system, the associated sensor must remain accurate, exhibit low drift and require no recalibration for extended periods of time.
Thus, an ideal implantable sensing apparatus would provide for a sensing apparatus that may be inserted into a vein, artery or other part of a body while being unobtrusive, easy to insert and remove, yet accurate and reliable. Embodiments of the present invention provides such a system.